1. Field of the Invention
The present invention relates to a lubricating system for a swash plate type compressor.
2. Description of the Related Art
Known in the prior art is a swash plate type compressor wherein a plurality of angularly spaced apart cylinder bores are formed in a stational cylinder block, pistons are axially slidably inserted into the cylinder bores, respectively, and at an axially central position of the cylinder block, a swash plate chamber is formed in which a swash plate is arranged (See U.S. Pat. No. 4,746,275 and U.S. Pat. No. 4,717,313). The swash plate is fixedly mounted to a drive shaft, and is connected to the middle portions of the pistons via respective shoes, so that the pistons are axially reciprocated in the respective cylinder bores in accordance with the rotation of the drive shaft. Pump chambers are formed on both ends of each of the pistons in the corresponding cylinder bore, and inlet chambers are formed at the sides of the cylinder block and are connected to the respective piston chambers for introducing a medium to be compressed when the movement of the respective pistons increases the volume of the pump chambers. Outlet chambers are formed on the sides of the cylinder block, concentrically to the inlet chambers, and are connected to the respective piston chambers for allowing the compressed fluid medium to be forced out of the piston chambers when the movement of the pistons reduces the volume of the pump chambers. An inlet port is opened to the swash plate chamber to allow an introduction of the medium to be compressed, and a plurality of angularly spaced inlet passageways are formed in the cylinder block and between the adjacent cylinder bores along the circumferential direction of the cylinder block. The inlet passageways connect the swash plate chamber to the inlet chambers.
A high speed sliding movement occurs between the swash plate and shoes under a compression reaction force, and thus a good lubrication of the shoes is very important. The cooling medium to be compressed contains a lubricant, and thus the lubricant is introduced into the swash plate chamber in an atomized condition and supplied to the shoes. The inlet port, however, is connected to the cylinder block at a position along the circumference of the swash plate chamber but the shoes are distributed along the entire circumference of the swash plate chamber, and as a result, the oil is apt to be locally supplied to the shoe located nearest the inlet port, and the lubrication of the remaining shoes located away from the inlet port is poor.